external/bsd/file/dist/src/fsmagic.c

   1 /*      $NetBSD: fsmagic.c,v 1.1.1.1 2009/05/08 16:35:06 christos Exp $ */
   2
   3 /*
   4  * Copyright (c) Ian F. Darwin 1986-1995.
   5  * Software written by Ian F. Darwin and others;
   6  * maintained 1995-present by Christos Zoulas and others.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice immediately at the beginning of the file, without modification,
  13  *    this list of conditions, and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  22  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  */
  30 /*
  31  * fsmagic - magic based on filesystem info - directory, special files, etc.
  32  */
  33
  34 #include "file.h"
  35
  36 #ifndef lint
  37 #if 0
  38 FILE_RCSID("@(#)$File: fsmagic.c,v 1.59 2009/02/03 20:27:51 christos Exp $")
  39 #else
  40 __RCSID("$NetBSD: fsmagic.c,v 1.1.1.1 2009/05/08 16:35:06 christos Exp $");
  41 #endif
  42 #endif  /* lint */
  43
  44 #include "magic.h"
  45 #include <string.h>
  46 #ifdef HAVE_UNISTD_H
  47 #include <unistd.h>
  48 #endif
  49 #include <stdlib.h>
  50 /* Since major is a function on SVR4, we cannot use `ifndef major'.  */
  51 #ifdef MAJOR_IN_MKDEV
  52 # include <sys/mkdev.h>
  53 # define HAVE_MAJOR
  54 #endif
  55 #ifdef MAJOR_IN_SYSMACROS
  56 # include <sys/sysmacros.h>
  57 # define HAVE_MAJOR
  58 #endif
  59 #ifdef major                    /* Might be defined in sys/types.h.  */
  60 # define HAVE_MAJOR
  61 #endif
  62
  63 #ifndef HAVE_MAJOR
  64 # define major(dev)  (((dev) >> 8) & 0xff)
  65 # define minor(dev)  ((dev) & 0xff)
  66 #endif
  67 #undef HAVE_MAJOR
  68
  69 private int
  70 bad_link(struct magic_set *ms, int err, char *buf)
  71 {
  72         const char *errfmt;
  73         int mime = ms->flags & MAGIC_MIME;
  74         if ((mime & MAGIC_MIME_TYPE) &&
  75             file_printf(ms, "application/x-symlink")
  76             == -1)
  77                 return -1;
  78         else if (!mime) {
  79                 if (err == ELOOP)
  80                         errfmt = "symbolic link in a loop";
  81                 else
  82                         errfmt = "broken symbolic link to `%s'";
  83                 if (ms->flags & MAGIC_ERROR) {
  84                         file_error(ms, err, errfmt, buf);
  85                         return -1;
  86                 }
  87                 if (file_printf(ms, errfmt, buf) == -1)
  88                         return -1;
  89         }
  90         return 1;
  91 }
  92
  93 private int
  94 handle_mime(struct magic_set *ms, int mime, const char *str)
  95 {
  96         if ((mime & MAGIC_MIME_TYPE)) {
  97                 if (file_printf(ms, "application/%s", str) == -1)
  98                         return -1;
  99                 if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms,
 100                     "; charset=") == -1)
 101                         return -1;
 102         }
 103         if ((mime & MAGIC_MIME_ENCODING) && file_printf(ms, "binary") == -1)
 104                 return -1;
 105         return 0;
 106 }
 107
 108 protected int
 109 file_fsmagic(struct magic_set *ms, const char *fn, struct stat *sb)
 110 {
 111         int ret = 0;
 112         int mime = ms->flags & MAGIC_MIME;
 113 #ifdef  S_IFLNK
 114         char buf[BUFSIZ+4];
 115         ssize_t nch;
 116         struct stat tstatbuf;
 117 #endif
 118
 119         if (ms->flags & MAGIC_APPLE)
 120                 return 0;
 121         if (fn == NULL)
 122                 return 0;
 123
 124         /*
 125          * Fstat is cheaper but fails for files you don't have read perms on.
 126          * On 4.2BSD and similar systems, use lstat() to identify symlinks.
 127          */
 128 #ifdef  S_IFLNK
 129         if ((ms->flags & MAGIC_SYMLINK) == 0)
 130                 ret = lstat(fn, sb);
 131         else
 132 #endif
 133         ret = stat(fn, sb);     /* don't merge into if; see "ret =" above */
 134
 135         if (ret) {
 136                 if (ms->flags & MAGIC_ERROR) {
 137                         file_error(ms, errno, "cannot stat `%s'", fn);
 138                         return -1;
 139                 }
 140                 if (file_printf(ms, "cannot open `%s' (%s)",
 141                     fn, strerror(errno)) == -1)
 142                         return -1;
 143                 return 1;
 144         }
 145
 146         if (!mime) {
 147 #ifdef S_ISUID
 148                 if (sb->st_mode & S_ISUID)
 149                         if (file_printf(ms, "setuid ") == -1)
 150                                 return -1;
 151 #endif
 152 #ifdef S_ISGID
 153                 if (sb->st_mode & S_ISGID)
 154                         if (file_printf(ms, "setgid ") == -1)
 155                                 return -1;
 156 #endif
 157 #ifdef S_ISVTX
 158                 if (sb->st_mode & S_ISVTX)
 159                         if (file_printf(ms, "sticky ") == -1)
 160                                 return -1;
 161 #endif
 162         }
 163
 164         switch (sb->st_mode & S_IFMT) {
 165         case S_IFDIR:
 166                 if (mime) {
 167                         if (handle_mime(ms, mime, "x-directory") == -1)
 168                                 return -1;
 169                 } else if (file_printf(ms, "directory") == -1)
 170                         return -1;
 171                 return 1;
 172 #ifdef S_IFCHR
 173         case S_IFCHR:
 174                 /*
 175                  * If -s has been specified, treat character special files
 176                  * like ordinary files.  Otherwise, just report that they
 177                  * are block special files and go on to the next file.
 178                  */
 179                 if ((ms->flags & MAGIC_DEVICES) != 0)
 180                         break;
 181                 if (mime) {
 182                         if (handle_mime(ms, mime, "x-character-device") == -1)
 183                                 return -1;
 184                 } else {
 185 #ifdef HAVE_STAT_ST_RDEV
 186 # ifdef dv_unit
 187                         if (file_printf(ms, "character special (%d/%d/%d)",
 188                             major(sb->st_rdev), dv_unit(sb->st_rdev),
 189                                         dv_subunit(sb->st_rdev)) == -1)
 190                                 return -1;
 191 # else
 192                         if (file_printf(ms, "character special (%ld/%ld)",
 193                             (long)major(sb->st_rdev), (long)minor(sb->st_rdev))
 194                             == -1)
 195                                 return -1;
 196 # endif
 197 #else
 198                         if (file_printf(ms, "character special") == -1)
 199                                 return -1;
 200 #endif
 201                 }
 202                 return 1;
 203 #endif
 204 #ifdef S_IFBLK
 205         case S_IFBLK:
 206                 /*
 207                  * If -s has been specified, treat block special files
 208                  * like ordinary files.  Otherwise, just report that they
 209                  * are block special files and go on to the next file.
 210                  */
 211                 if ((ms->flags & MAGIC_DEVICES) != 0)
 212                         break;
 213                 if (mime) {
 214                         if (handle_mime(ms, mime, "x-block-device") == -1)
 215                                 return -1;
 216                 } else {
 217 #ifdef HAVE_STAT_ST_RDEV
 218 # ifdef dv_unit
 219                         if (file_printf(ms, "block special (%d/%d/%d)",
 220                                         major(sb->st_rdev), dv_unit(sb->st_rdev),
 221                                         dv_subunit(sb->st_rdev)) == -1)
 222                                 return -1;
 223 # else
 224                         if (file_printf(ms, "block special (%ld/%ld)",
 225                                         (long)major(sb->st_rdev), (long)minor(sb->st_rdev)) == -1)
 226                                 return -1;
 227 # endif
 228 #else
 229                         if (file_printf(ms, "block special") == -1)
 230                                 return -1;
 231 #endif
 232                 }
 233                 return 1;
 234 #endif
 235         /* TODO add code to handle V7 MUX and Blit MUX files */
 236 #ifdef  S_IFIFO
 237         case S_IFIFO:
 238                 if((ms->flags & MAGIC_DEVICES) != 0)
 239                         break;
 240                 if (mime) {
 241                         if (handle_mime(ms, mime, "x-fifo") == -1)
 242                                 return -1;
 243                 } else if (file_printf(ms, "fifo (named pipe)") == -1)
 244                         return -1;
 245                 return 1;
 246 #endif
 247 #ifdef  S_IFDOOR
 248         case S_IFDOOR:
 249                 if (mime) {
 250                         if (handle_mime(ms, mime, "x-door") == -1)
 251                                 return -1;
 252                 } else if (file_printf(ms, "door") == -1)
 253                         return -1;
 254                 return 1;
 255 #endif
 256 #ifdef  S_IFLNK
 257         case S_IFLNK:
 258                 if ((nch = readlink(fn, buf, BUFSIZ-1)) <= 0) {
 259                         if (ms->flags & MAGIC_ERROR) {
 260                             file_error(ms, errno, "unreadable symlink `%s'",
 261                                 fn);
 262                             return -1;
 263                         }
 264                         if (mime) {
 265                                 if (handle_mime(ms, mime, "x-symlink") == -1)
 266                                         return -1;
 267                         } else if (file_printf(ms,
 268                             "unreadable symlink `%s' (%s)", fn,
 269                             strerror(errno)) == -1)
 270                                 return -1;
 271                         return 1;
 272                 }
 273                 buf[nch] = '\0';        /* readlink(2) does not do this */
 274
 275                 /* If broken symlink, say so and quit early. */
 276                 if (*buf == '/') {
 277                         if (stat(buf, &tstatbuf) < 0)
 278                                 return bad_link(ms, errno, buf);
 279                 } else {
 280                         char *tmp;
 281                         char buf2[BUFSIZ+BUFSIZ+4];
 282
 283                         if ((tmp = strrchr(fn,  '/')) == NULL) {
 284                                 tmp = buf; /* in current directory anyway */
 285                         } else {
 286                                 if (tmp - fn + 1 > BUFSIZ) {
 287                                         if (ms->flags & MAGIC_ERROR) {
 288                                                 file_error(ms, 0,
 289                                                     "path too long: `%s'", buf);
 290                                                 return -1;
 291                                         }
 292                                         if (mime) {
 293                                                 if (handle_mime(ms, mime,
 294                                                     "x-path-too-long") == -1)
 295                                                         return -1;
 296                                         } else if (file_printf(ms,
 297                                             "path too long: `%s'", fn) == -1)
 298                                                 return -1;
 299                                         return 1;
 300                                 }
 301                                 /* take dir part */
 302                                 (void)strlcpy(buf2, fn, sizeof buf2);
 303                                 buf2[tmp - fn + 1] = '\0';
 304                                 /* plus (rel) link */
 305                                 (void)strlcat(buf2, buf, sizeof buf2);
 306                                 tmp = buf2;
 307                         }
 308                         if (stat(tmp, &tstatbuf) < 0)
 309                                 return bad_link(ms, errno, buf);
 310                 }
 311
 312                 /* Otherwise, handle it. */
 313                 if ((ms->flags & MAGIC_SYMLINK) != 0) {
 314                         const char *p;
 315                         ms->flags &= MAGIC_SYMLINK;
 316                         p = magic_file(ms, buf);
 317                         ms->flags |= MAGIC_SYMLINK;
 318                         return p != NULL ? 1 : -1;
 319                 } else { /* just print what it points to */
 320                         if (mime) {
 321                                 if (handle_mime(ms, mime, "x-symlink") == -1)
 322                                         return -1;
 323                         } else if (file_printf(ms, "symbolic link to `%s'",
 324                             buf) == -1)
 325                                 return -1;
 326                 }
 327                 return 1;
 328 #endif
 329 #ifdef  S_IFSOCK
 330 #ifndef __COHERENT__
 331         case S_IFSOCK:
 332                 if (mime) {
 333                         if (handle_mime(ms, mime, "x-socket") == -1)
 334                                 return -1;
 335                 } else if (file_printf(ms, "socket") == -1)
 336                         return -1;
 337                 return 1;
 338 #endif
 339 #endif
 340         case S_IFREG:
 341                 break;
 342         default:
 343                 file_error(ms, 0, "invalid mode 0%o", sb->st_mode);
 344                 return -1;
 345                 /*NOTREACHED*/
 346         }
 347
 348         /*
 349          * regular file, check next possibility
 350          *
 351          * If stat() tells us the file has zero length, report here that
 352          * the file is empty, so we can skip all the work of opening and
 353          * reading the file.
 354          * But if the -s option has been given, we skip this optimization,
 355          * since on some systems, stat() reports zero size for raw disk
 356          * partitions.  (If the block special device really has zero length,
 357          * the fact that it is empty will be detected and reported correctly
 358          * when we read the file.)
 359          */
 360         if ((ms->flags & MAGIC_DEVICES) == 0 && sb->st_size == 0) {
 361                 if (mime) {
 362                         if (handle_mime(ms, mime, "x-empty") == -1)
 363                                 return -1;
 364                 } else if (file_printf(ms, "empty") == -1)
 365                         return -1;
 366                 return 1;
 367         }
 368         return 0;
 369 }